1. Technical Field
The present disclosure relates to a technique for authenticating a device connected to an area network and relates specifically to a technique for performing mutual authentication between a controller and a device and updating a group key.
2. Description of the Related Art
Currently, services that utilize various types of history information collected by a cloud server from home electrical appliances, AV devices, household equipment, and other devices having a network connection function (hereinafter simply referred to as “devices”) are anticipated. A network formed by connecting devices installed in a home with one another is hereinafter referred to as a home area network.
In some cases, a specific device (hereinafter referred to as “controller”) is connected to the home area network, and communication between the devices and an external server is performed via the controller. In such cases, it is necessary to control communication in the home by securely making connections between the controller and the devices and to prevent connections from being made by an unauthorized device conducting spoofing activity or information from leaking out by interception of the content of communication, for example. Countermeasures, such as authentication of a device to be connected, can be taken against the former case, and countermeasures, such as encryption of communication, can be taken against the latter case, for example. The controller and a device whose validity has been confirmed share an encryption key and perform encrypted communication with each other using the encryption key. In a case where there are a plurality of devices that are to be connected to the controller, the controller and the devices share the same encryption key (hereinafter referred to as “group key”) to thereby enable encryption of multicast communication or broadcast communication in which the controller simultaneously transmits the same information to the plurality of devices.
In existing authentication systems as described above, group keys need to be further improved.